The present invention relates to the transfer of information to a portable client device and more particularly to a method of transferring data from a host computer system in which the data is displayed in the form of an optical bit stream on a display monitor connected to a host computer system and in which the optical bit stream is then detected and downloaded using an optical sensing device that is connected to the client device. The advantage of this method is that it can be implemented on any computer system that is connected to any display monitor that is capable of displaying an on/off light, such as a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD).
The use of portable information devices is growing and the number of applications for such devices continues to expand. Examples of such devices include portable electronic devices such as personal digital assistants (PDA""s), smart phones, electronic organizers, video game units, watches, digital music players, video players, and laptop computers. The corresponding growth in networked computers, and in particular the rapid expansion of commercial use of the Internet, is spurring the proliferation of portable information devices which in turn highlights the need to download data to these devices. For example, one may wish to download the latest software update to a video game or digital music selections from the Internet. The Internet refers to the network of computers that arose out of the network created by the Advanced Research Projects Agency (ARPA) using the transmission control protocol/Internet protocol (TCP/IP) as the method for providing communication between the computers on the network. A number of service facilities have been developed to access and transfer information across the Internet and one of the most popular is known as the World Wide Web (WWW). Typically, a user would access data on the WWW by interfacing with software known as a Web browser, running on a client computer that is connected to the Internet. Alternatively, one may wish to download calendar information from the computer at the office, and later download airline schedules from a kiosk at the airport using a PDA. In this example, the network of computers at the office and the network to which the kiosk is connected at the airport may each be separate, internal and private to an organization with restricted accessibility. Such a private network is often referred to as an Intranet, as compared to the relatively more accessible Internet. Thus, it would be desirable to be able to download information to a variety of portable electronic devices in a wide variety of situations on both the Internet or a private Intranet.
Information that is stored on a computer system can be transferred to another computer or device using a variety of communication methods. The information is transmitted in the form of binary data according to one of a variety of standard schemes using either serial or parallel encoding methods. Such methods may include protocols for handshake procedures, starting, stopping, and error detection and correction. Loading software or data from a host computer system to an external device typically requires either a wired connection between the host computer and the external device, or possibly a wireless connection using an infrared or radio frequency (RF) port, which both require specialized hardware not only on the client device, but also on the host system. This requirement for additional hardware on both the host and client restricts the flexibility of the data transfer and may be difficult to accommodate in some, perhaps remote, locations. Therefore there is a need for a wireless transfer method that does not require matching hardware or hardwired connections, in order to increase the flexibility and usability of portable information devices.
One technique of downloading data that does not require hardwired connections is disclosed in U.S. Pat. No. 5,488,571 entitled xe2x80x9cMethod and Apparatus for Downloading Information from a Controllable Light Source to a Portable Information Device,xe2x80x9d issued to Jacobs et al. on Jan. 30, 1996 (hereinafter referred to as the Jacobs patent). The Jacobs patent describes a method and apparatus for transferring data from a CRT display on a personal computer to a multifunction electronic wristwatch. In the Jacobs patent, the data is formatted as a serial bit stream, and the bit stream is then displayed in the form of lines of varying brightness on a CRT display in accordance with the raster refresh rates of the CRT display. The data is transferred to an electronic watch through the use of a photo sensor which detects the light pulses displayed on the CRT as binary data in accordance with timing information associated with the raster scan rate of the CRT. The Jacobs patent is therefore limited to the use of CRT displays and cannot be used with other types of displays such as LCD displays because timing information is dependent on the raster scan rate of the CRT. In addition, the Jacobs patent is also limited to using a serial transmission scheme.
It is an object of the present invention to provide a method of information transfer from a host computer system to a portable client information device that enables optical data transmission through the use of display monitors in a manner that is independent of the type of display monitor.
It is another object of the present invention to provide a method of information transfer from a host computer system to a portable device that can be utilized in conjunction with the Internet or other computer networks.
It is another object of the present invention to provide a method of information transfer that can accommodate a variety of communications protocol standards, and transmit data using either serial or parallel encoding schemes.
According to the present invention, a method is provided for performing optical data transmission to a portable information device, said method comprising the steps of:
(a) encoding the source data to be downloaded into a data bit stream;
(b) generating a clocking bit stream representing timing pulses;
(c) displaying said clocking bit stream by illuminating a first set of pixels sequentially in accordance with said timing pulses, and displaying said data bit stream by illuminating another set of pixels synchronously with said clocking bit stream so that a bit of data is displayed during the same period of time that a timing pulse is displayed; and
(d) detecting the light pulses displayed on the screen using an optical sensing device that is configured to separately detect the illumination of said sets of pixels, converting said light pulses into decoded data and storing the decoded data within the portable information device.
Thus, according to a preferred embodiment of the present invention, a user who desires to download data accesses a host computer via a Web browser thereby invoking a program (such as an applet running in conjunction with the browser environment) to display a regulated series of light pulses which represent a bit stream of data being downloaded. In this embodiment, step (c) of displaying the bit stream data is implemented using a color monitor capable of displaying three primary colors such as red, green, and blue (RGB) whereby each primary color is activated by a separate video signal. The color of a given picture element (pixel) of a display screen is achieved generally by an appropriate combination of the relative brightness of RGB dots as known by those skilled in the art. The transmission of data according to the present invention is accomplished by illuminating the pixels comprising one primary color within a prescribed area of the display screen at intervals of time in accordance with the clocking bit stream (in other words, a series of light pulses), and similarly illuminating a different set of pixels within the same prescribed area comprising another primary color so that a bit of data information is displayed during the time increment in which a clocking light pulse is illuminated. The prescribed area in which the light pulses are displayed is referred to hereinafter as an xe2x80x9cOptical Zonexe2x80x9d (OZ). One color (for example, blue) is used as a clock synchronization pulse. A remaining primary color (for example, red) is used to display light pulses representing a data bit stream. The third remaining color, green in this example, could be used to display another data bit stream. Thus, each separately illuminated colored set of pixels acts effectively as an individual transmission xe2x80x9cchannel.xe2x80x9d Step (d) of detecting the light pulses is performed by an optical sensing device that is connected to the portable information device and is configured to detect each primary color separately and concurrently.
The present invention also provides for a plurality of Optical Zones (OZ""s), such that two or more OZ""s are formed. Each OZ is used to display a separate output bit stream, and each bit stream is displayed in the form of optical pulses which are synchronized according to the clocking bit stream. Thus a collection of two or more optical zones will hereinafter be referred to as an xe2x80x9cOptical Zone Multiple Output Neighborhoodxe2x80x9d (OZMON). The present invention allows for the possibility of using a parallel transmission scheme to encode the data. For example, two colors within a first optical zone may be used to encode the data bit streams according to a parallel transmission scheme that uses two data channels. By adding another OZ to form an OZMON, the two colors within the first optical zone may be used in combination with each of the three colors in each additional output neighborhood as separate additional parallel data transmission channels, thus increasing the effective transmission bandwidth. The optical sensing device used to detect the light pulses would be configured to detect each primary color separately and concurrently within each OZ of the OZMON.
An alternative embodiment is applicable if the display monitor is a monochrome display capable of illuminating only pixels of one color as a result of having only one input video signal. An OZMON comprising two or more OZ""s is used to display the light pulses. A first OZ is dedicated to the display of the clocking bit stream, and the remaining one or more OZ""s of the OZMON are used to display data bit stream light pulses. Correspondingly, the optical sensing device is configured to detect the light pulses from each OZ separately and concurrently.
Another alternative embodiment of the present invention uses a serial transmission scheme in step (a) of encoding the source data into one data bit stream. In the case of a color display monitor, this embodiment utilizes a single OZ and uses only two primary colors as transmission channels. In the case of a monochrome display, this embodiment utilizes an OZMON comprising two OZ""s, a first optical zone dedicated to the clocking bit stream, and the second optical zone dedicated to the data bit stream. This embodiment provides for sensing device used in step (d) that has a minimum configuration.
The novel features believed to be characteristic of this invention are set forth in the appended claims. The invention itself, however, as well as other objects and advantages thereof, may be best understood by reference to the following detailed description of an illustrated preferred embodiment to be read in conjunction with the accompanying drawings.